Me and my friend are working on online game project and for beginning we use TCP connection made by java. What do I have to do to successfuly make my friends client connect to my server? On local host it works perfectly. What are the reqiurements for this?
Check to make sure that your firewall allows connections from remote hosts to your computer on the port you are hosting the game on. If you friend is connecting to your computer from another location you will most likely need to add a firewall rule to your router.
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Heyy guys. I'm writing a chat application in java, works pretty well. But can i somehow host my Server file or the Serversocket on the web? I want to make it so my friends from other pcs can use the client and connect to the server file which is hosted on the web. Is that possible? Can i host the File/socket online?
When you run a java application that opens a ServerSocket, it opens a port on your local machine and starts listening for incoming connections. What you do with those connections is up to the implementation of the java code that you write.
The "web" is much less foreign than you are making it out to be. Your own computer can be on the web that you're talking about and people can connect to your chat service. Or you can choose to host it on something like an AWS server.
The following approach is assuming you are behind a pretty standard NAT config.
Once you run your java application, you need to make sure other computers can see you, either inside your LAN or outside on the internet. You want to start testing from as close to your computer as possible, then start expanding outward.
First you need to make sure that your computer's firewall is actually allowing connections on the port that your java application is listening on.
Opening ports in the Windows Firewall
Setting up and opening ports in Linux
Now computers on your LAN will be able to connect to your java program. Now you need to go one layer out, and port forward your router. This is much less standard so I can't help you too much, but Google can.
At this point, anyone on this internet, knowing your external ip and what port your java application is listening, can connect to your service.
If you chose to host this on an third party hosting service, you'll need to go through similar steps, but there may be slight differences that you can either ask about, or again Google is a great resource.
I have absolutely no idea what I am doing wrong. About a month ago, I set up my router to work with a server/socket connection in Java. I just moved back to my apartment, and am using a different router with a different ip in a different area.
Connecting to localhost (as the default) with my ServerSocket, and then connecting to the ip I get from whatsmyip.org as the hostname for the client socket, shouldn't I be able to connect?
The server and client are running on the same computer, and if I switch the hostname of the client to localhost, the connection works perfectly. I have a port forwarding set up to my computer's ip address that the router gets for me (not from whatsmyip.org) to port 1640, which is what I was using back at my old place where it was working. What am I doing wrong here?
EDIT 1: I am using DynDNS.com to set up a hostname URL that links to my computer's IP, which I then have all of the clients connect to. The client program can be on any computer anywhere. Before I switch routers, this was working perfectly. I was using the Dynamic DNS feature of the router using my DynDNS account, which was set up on my old router, and my new one. So basically, I should just use my old router?
Some routers will not route the external IP while you are on the internal network. I had a router which was like this. Try connecting from an external location (have a friend try, connect to a remote server and connect back in, or use a device connected to 3G wireless etc).
But im not sure from your question if you actually want to connect from the outside. If you dont, there is no need to creating the port forward (in fact you are just making your server visible to the world unnecessarily). Use the local address of your machine (192.168.x.x / 10.1.1.* etc depending on your router) from any machine within your LAN.
I have fully developed a chat room for multiple clients with multi-threaded server which does the job, however only on my local machine. I want to go beyond this, and make this chat room to be working over the internet. So far I have made the port forwarding on my router for TCP protocol to route to my local IP address, however this didn't solve the problem and I still can't connect the client, even on my own local network. What other steps should I follow to get my chat room working on my own local network and then the internet?
try disable (windows) firewall ?
So my friend the basic rule for make anything to work over internet is to do Port forwarding or in simple way you can say that to open your server for the public network. For that you need to make sure that the routing path is complete from internet machines to your desktop. For this to work you need to open the port for which you need to access your machine from firewall settings, and also ensuring that trafic is routed from your public IP address to the server's IP as your server will be private under some router or ISP.
Way to do that:
You need to configure your home network i.e router setting. So in your router, configure the port you want the communication to happen(say port 5443).
In your router, configure a port-forward for the port 5443 to the internal IP address of your actual server, also to port 5443.
Reference: https://www.noip.com/support/knowledgebase/general-port-forwarding-guide/
On your server(your Desktop Machine) ensure that your firewall settings for port 5443 is on and set to allow rather than block.
I recently developed an Android application with which the Android device can communicate with another Android device running the application.
The communication works over sockets, therefore I developed a server which i run on my computer.
Here is my problem:
The communication between the devices over the Server running on my PC works fine, as long as all devices as well as the PC are in the same LAN (connected over the same Router for example).
Now I want to get the server online, so that the Android devices can connect to the "online" server and communicate with each other over the server from anywhere.
I simply have no idea of how to get the server online and running. How can I do that?
The main issue is, that I know about Client/Server communication locally, but have no experience in the "online" sector.
It is more a network problem than a programming one. Your server open a socket and therefore is available to anyone able to reach that socket.
You have to do a redirection on your router. The problem is that your machine doesn't have a public IP, only your router has one. So when your router receive a packet on port 21 for example, it doesn't know what to do with it. You have to configure it to say "the port 21 has to redirected to the local IP XXX"
Also the public IP of your modem/router can change, depending on your ISP. If your have a fixed IP, it won't change, otherwise you will have to install a software like dyndns to have a domain name associated with your IP.
Im using TCP/IP sockets in java to try and create a client-server application. The program works fine when run locally and also over the local area network, but when I use the internet IP address the clients connection is refused.
I used this website to get my IP address and have added a firewall entry to unblock the port im using (port 4445).
I am almost certain the problem lies in some sort of security measure that is blocking the port. Does it matter that I'm running the client and server on the same PC but using the IP address from the previously mentioned website?
If I could get a list of ways to test the port is in fact open, or a list of things to try in order to get my program running, that would be great!
That website may very likely give you the IP address of the gateway through which your PC is connecting to the internet, and if the gateway is out of your control (which is most of the cases as far as I know) there's nothing you can do to use that IP address to test your program. Here's some advice:
Try http://aws.amazon.com, once registered you have one-year free access to a micro-server (which can be accessed publicly through DNS/Elastic IP.)
If your PC have a public IP address, you don't need that website to find out what it is. Just check your network adapter control panel.
Where is the server has been located? If your server is located in some commercial hosting, there is possibility that the ports you use are blocked. Also if you use modem with router or just router in your local network you should check nat table.